Journal articles on the topic 'Pratylenchus thornei'
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FATEMI, EHSAN, and HABIBALLAH CHAREHGANI. "Root Lesion Nematode Pratylenchus thornei." Plant Pathology Science 7, no. 1 (March 1, 2018): 28–39. http://dx.doi.org/10.29252/pps.7.1.28.
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Bucki, Patricia, Xue Qing, Pablo Castillo, Abraham Gamliel, Svetlana Dobrinin, Tamar Alon, and Sigal Braun Miyara. "The Genus Pratylenchus (Nematoda: Pratylenchidae) in Israel: From Taxonomy to Control Practices." Plants 9, no. 11 (November 2, 2020): 1475. http://dx.doi.org/10.3390/plants9111475.
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Due to Israel’s successful agricultural production and diverse climatic conditions, plant-parasitic nematodes are flourishing. The occurrence of new, previously unidentified species in Israel or of suggested new species worldwide is a consequence of the continuous withdrawal of efficient nematicides. Among plant-parasitic nematodes, migratory endoparasitic species of the genus Pratylenchus are widely distributed in vegetable and crop fields in Israel and are associated with major reductions in quality and yield. This review focuses on the occurrence, distribution, diagnosis, pathogenicity, and phylogeny of all Pratylenchus species recorded over the last few decades on different crops grown throughout Israel—covering early information from nematologists to recent reports involving the use of molecular phylogenetic methodologies. We explore the accepted distinction between Pratylenchus thornei and Pratylenchus mediterraneus isolated from Israel’s northern Negev region, and address the confusion concerning the findings related to these Pratylenchus species. Our recent sampling from the northern Negev revealed the occurrence of both P. thornei and P. mediterraneus on the basis of molecular identification, indicating P. mediterraneus as a sister species of P. thornei and their potential occurrence in a mixed infection. Finally, the efficiencies of common control measures taken to reduce Pratylenchus’ devastating damage in protected crops and field crops is discussed.
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Smiley, Richard W., Guiping Yan, and Jennifer A. Gourlie. "Selected Pacific Northwest Rangeland and Weed Plants as Hosts of Pratylenchus neglectus and P. thornei." Plant Disease 98, no. 10 (October 2014): 1333–40. http://dx.doi.org/10.1094/pdis-12-13-1295-re.
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Eighteen rangeland plants and 16 weed species were assayed in the greenhouse for efficiency as hosts of Pratylenchus neglectus and P. thornei. Hosting ability ratings were assigned using the ratio of final versus initial nematode density and by comparing the final nematode density to that of susceptible wheat controls. Good hosts of both Pratylenchus spp. included thickspike bluegrass ‘Critana’, smooth brome ‘Manchar’, seven wheatgrasses, and jointed goatgrass. Good hosts of P. neglectus but not P. thornei included two hairy vetches, western wheatgrass ‘Rosana’, big bluegrass ‘Sherman’, tall wheatgrass ‘Alkar’, green foxtail, kochia, large crabgrass, palmer amaranth, redroot pigweed, tumble mustard, and wild oat. Good hosts of P. thornei but not P. neglectus included hard fescue ‘Durar’, sheep fescue ‘Blacksheep’, downy brome, and rattail fescue. Poor or minor hosts of both Pratylenchus spp. included two alfalfas, dandelion, horseweed, lambsquarters, prostrate spurge, and Russian thistle. These assays will provide guidance for transitioning rangeland into crop production and for understanding the role of weeds on densities of Pratylenchus spp. in wheat-production systems.
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Smiley, Richard W., Guiping Yan, and Jennifer A. Gourlie. "Selected Pacific Northwest Crops as Hosts of Pratylenchus neglectus and P. thornei." Plant Disease 98, no. 10 (October 2014): 1341–48. http://dx.doi.org/10.1094/pdis-12-13-1296-re.
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Thirty crop species and cultivars were assayed in the greenhouse for efficiency as hosts of Pratylenchus neglectus and P. thornei. Hosting ability ratings were assigned using the ratio of final versus initial nematode density and also by comparing the final nematode density to that of a susceptible wheat control. Good hosts of both Pratylenchus spp. included oat ‘Monida’, chickpea ‘Myles’, and lentil ‘Athena’ and ‘Morton’. Good hosts of P. neglectus but not of P. thornei included 10 Brassica spp. (5 canola, 2 mustard, and 3 camelina cultivars), chickpea ‘Sierra’, sudangrass ‘Piper’, and sorghum/sudangrass hybrid ‘Greentreat Plus’. Good hosts of P. thornei but not of P. neglectus included lentil ‘Skyline’ and pea ‘Granger’, ‘Journey’, and ‘Universal’. Poor or minor hosts of both Pratylenchus spp. included chickpea ‘Dwelley’, pea ‘Badminton’, safflower ‘Gila’, ‘Girard’, and ‘KN 144’, sunflower ‘2PD08’, flax ‘Pembina’, eastern gamagrass ‘Pete’, and switchgrass ‘Blackwell’. Results of these assays will provide guidance for improving crop rotation and cultivar selection efficiencies.
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Rahaman, Md Motiur, Rebecca S. Zwart, and John P. Thompson. "Constitutive and Induced Expression of Total Phenol and Phenol Oxidases in Wheat Genotypes Ranging in Resistance/Susceptibility to the Root-Lesion Nematode Pratylenchus thornei." Plants 9, no. 4 (April 9, 2020): 485. http://dx.doi.org/10.3390/plants9040485.
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Plant-derived phenolic compounds contribute to the defense against various pathogens, including root-lesion nematodes (Pratylenchus spp.). However, there are no reports on the role of phenolic compounds in wheat (Triticum aestivum) against Pratylenchus thornei. In this study, wheat genotypes ranging from resistant to very susceptible to P. thornei were used to investigate the level of total phenols and phenol oxidases, polyphenol oxidase (PPO), and peroxidase (POD) expressed in root tissues when grown in the presence and absence of P. thornei over time (2–8 weeks). Higher constitutive levels of total phenols were found in resistant synthetic hexaploid wheats CPI133872 (576 µg gallic acid equivalent (GAE)/g root) and CPI133859 (518 µg GAE/g root) at 8 weeks after sowing, compared with moderately resistant and susceptible genotypes (192 to 390 µg GAE/g root). The activity of PPO was induced in resistant (CPI133872) and moderately resistant (GS50a and its derivate QT8343) genotypes, becoming maximal at 4 weeks after P. thornei inoculation. The activity of POD was induced in CPI133872 at 6 weeks after P. thornei inoculation. Different genetic sources of resistance to P. thornei showed diverse defense mechanisms and differences in timing responses. The combined effects of total phenols and oxidative enzymes could be important for defense against P. thornei in some resistant wheat genotypes.
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Majd Taheri, Zahra, Zahra Majd Taheri, Zahra Tanha Maafi, Zahra Majd Taheri, Zahra Tanha Maafi, Sergei A. Subbotin, Zahra Majd Taheri, et al. "Molecular and phylogenetic studies on Pratylenchidae from Iran with additional data on Pratylenchus delattrei, Pratylenchoides alkani and two unknown species of Hirschmanniella and Pratylenchus." Nematology 15, no. 6 (2013): 633–51. http://dx.doi.org/10.1163/15685411-00002707.
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Thirteen species of Pratylenchidae: Pratylenchus coffeae, P. delattrei, P. loosi, P. neglectus, P. penetrans, P. pseudopratensis, P. thornei, P. vulnus, Pratylenchus sp., Pratylenchoides alkani, P. ritteri, Hirschmanniella sp. and Zygotylenchus guevarai were collected from different crops and plants throughout Iran. The specimens were identified using morphological and molecular methods. Morphometrics and morphology are given for Pratylenchus sp., P. delattrei, Pratylenchoides alkani and Hirschmanniella sp. The D2-D3 expansion segments of the 28S rRNA gene were amplified and sequenced for all 13 species studied. Diagnostic PCR-ITS-RFLP profiles are given for Pratylenchus delattrei, P. penetrans, P. pseudopratensis, Pratylenchus sp., Pratylenchoides alkani and P. ritteri. Pratylenchus neglectus and P. thornei, collected from cereal fields, P. loosi from tea plantations, P. coffeae from banana, P. penetrans from ornamental plants, P. vulnus from pines and Z. guevarai from almonds showed a high level of similarity in the D2-D3 sequences with corresponding GenBank sequences. Nucleotide differences between Iranian populations and reference species were in the intraspecific range. Pratylenchus delattrei, found in vegetable fields, and Pratylenchus sp. from palm rhizosphere, formed a highly supported clade with P. zeae, the two former species being morphologically very close to the latter except in tail shape. Pratylenchus pseudopratensis, from cereal fields, clustered with P. vulnus with low support. Phylogenetic relationships within Pratylenchus species were mainly congruent with those obtained in previous studies. Despite the morphological similarities between P. ritteri and P. alkani, the D2-D3 of 28S rRNA gene sequences differed by 5 bp. Hirschmanniella sp., from a rice field, formed a clade with H. loofi and H. kwazuna.
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Dababat, Abdelfattah A., Fouad Mokrini, Salah-Eddine Laasli, Şenol Yildiz, Gül Erginbas-Orakci, Nagihan Duman, and Mustafa Ímren. "Host suitability of different wheat lines to Pratylenchus thornei under naturally infested field conditions in Turkey." Nematology 21, no. 6 (2019): 557–71. http://dx.doi.org/10.1163/15685411-00003235.
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Summary The root-lesion nematode, Pratylenchus thornei, attacks a wide range of crops and causes significant reductions in global grain production. Breeding programmes are currently restricted to using parents with moderate resistance to P. thornei as cereal cultivars with complete resistance are yet to be identified. This study evaluated 484 of CIMMYT’s spring wheat accessions for resistance to P. thornei of which 56 lines were pre-identified as resistant under controlled growth room conditions. These lines were further evaluated for their resistance and tolerance reactions under field conditions, where 14 accessions maintained their resistance and 16 were moderately resistant against P. thornei. Four lines gave excellent resistant and tolerance reactions to P. thornei. The relationship between the nematode reproduction factor (Pf/Pi) and wheat grain yield in field experiments fits a linear regression model. These findings could be useful for improving P. thornei resistance in wheat.
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Confort, Pedro Marcus de Souza, and Mario Massayuki Inomoto. "Pasteuria thornei, a novel biological seed treatment for Pratylenchus brachyurus control in soybean." Nematology 20, no. 6 (2018): 519–23. http://dx.doi.org/10.1163/15685411-00003156.
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Summary The goal of this study was to evaluate the efficiency of Pasteuria thornei as a biological seed treatment for Pratylenchus brachyurus control in soybean (Glycine max). Seeds of soybean ‘SYN1080’ were treated with three concentrations of P. thornei endospores per seed (5 × 106, 107, 1.5 × 107), together with two other treatments for comparison: a commercial control containing abamectin (0.58 mg seed−1) and a mixed treatment containing abamectin (0.58 mg seed−1) and 107 endospores of P. thornei. These seeds were sown in plastic cups containing soil inoculated with 1000 nematodes (Trial 1) and 600 nematodes (Trial 2). The trials were evaluated at 60 and 90 days after inoculation (dai). The total of nematodes extracted from the roots of each plant was used as the assessment criterion. Only the highest concentration of P. thornei endospores (1.5 × 107) consistently reduced the final populations of P. brachyurus by 25-50% compared to the non-treated seeds. The treatments containing abamectin were superior in reducing the nematode population in all trials and evaluations. There was no visible synergistic effect of the combined use of abamectin and P. thornei in the same treatment at 90 dai.
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Fanning, Joshua P., Karyn L. Reeves, Clayton R. Forknall, Alan C. McKay, and Grant J. Hollaway. "Pratylenchus thornei: The Relationship Between Presowing Nematode Density and Yield Loss in Wheat and Barley." Phytopathology® 110, no. 3 (March 2020): 674–83. http://dx.doi.org/10.1094/phyto-08-19-0320-r.
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The root lesion nematode Pratylenchus thornei causes economic losses in wheat and barley internationally through both reduced grain yield and grain quality. This study investigated the relationships between the presowing P. thornei density and grain yield and the postharvest nematode densities. Four field experiments were conducted at the same site between 2010 and 2014. A range of presowing P. thornei densities was established in the first year by growing three cereal cultivars that ranged from resistant to susceptible. In the following year, plots were sown with the five same cereal cultivars. A linear relationship was observed between the natural log of the presowing P. thornei density and grain yield across all seasons. The results showed that grain yield losses varied between cultivars and seasons. The importance of season was significant, with this study conducted over several seasons, and it highlighted the variability in yield losses between seasons, which will need further investigation. The greatest yield losses observed were 25 to 28% when the maximum presowing P. thornei densities ranged between 150 and 250 P. thornei g of soil−1. An analysis of the relationship between the presowing and postharvest nematode densities revealed that increased presowing nematode densities resulted in decreased multiplication rates in all seasons and in all cultivars. Nematode multiplication rates also varied between seasons. These results explain why it is difficult to predict nematode levels based on cropping history, and additionally, they highlight the importance of growing resistant cultivars to maintain low levels of P. thornei to minimize risk of yield losses.
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Yan, Guiping, Richard W. Smiley, and Patricia A. Okubara. "Detection and Quantification of Pratylenchus thornei in DNA Extracted from Soil Using Real-Time PCR." Phytopathology® 102, no. 1 (January 2012): 14–22. http://dx.doi.org/10.1094/phyto-03-11-0093.
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The root-lesion nematode Pratylenchus thornei is one of the most important pests restricting productivity of wheat in the Pacific Northwest (PNW). It is laborious and difficult to use microscopy to count and identify the nematodes in soils. A SYBR Green I-based real-time polymerase chain reaction (PCR) assay was developed to detect and quantify this species from DNA extracts of soil. A primer set, designed from the internal transcribed spacer region (ITS1) of rDNA, was highly specific to P. thornei and did not amplify DNA from 27 isolates of other Pratylenchus spp., other nematodes, and six fungal species present in PNW wheat fields. A standard curve relating threshold cycle and log values of nematode number was generated from artificially infested soils. The standard curve was supported by a high correlation between the numbers of P. thornei added to soil and the numbers quantified using real-time PCR. Examination of 15 PNW dryland field soils and 20 greenhouse samples revealed significant positive correlations between the numbers determined by real-time PCR and by the Whitehead tray and microscopic method. Real-time PCR is a rapid, sensitive alternative to time-consuming nematode extractions, microscopic identification, and counting of P. thornei from field and greenhouse soils.
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Riley, I. T., and S. J. Kelly. "Endoparasitic nematodes in cropping soils of Western Australia." Australian Journal of Experimental Agriculture 42, no. 1 (2002): 49. http://dx.doi.org/10.1071/ea01054.
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Soil samples were collected in Western Australia from cereal fields at about harvest time to determine levels of the endoparasitic nematodes, Pratylenchus and Heterodera. A systematic survey in 1997 and 1998 centred on the 40 shires with the highest proportion of cereal cropping. One hundred and eighty samples were collected in 1997 and 227 in 1998 at 10-km intervals along north–south transects 35 km apart. A targeted survey in 1997 included 98 soil samples from fields selected by growers as having poor productivity without an evident cause. No Heterodera cysts were found in any survey sample but these could be extracted from soils previously known to be infested. Pratylenchus neglectus was most commonly detected followed by P. thornei and P. zeae. Populations identified as P. brachyurus, P. penetrans, P. scribneri, and an undescribed species similar to P. thornei were also found. Overall Pratylenchus was extracted from 63% of samples (mean 1.1, median 0.3, max. 22.0/mL of soil). Maps of the data indicate that Pratylenchus populations were aggregated with some areas having relatively light infestations. There was a positive relationship with the intensity of cereal cropping and a negative relationship with pulse cropping. The findings indicate that potentially damaging Pratylenchus numbers occur in a significant proportion of fields and highlight the need to develop and implement strategies to lower population densities.
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Owen, K. J., T. G. Clewett, and J. P. Thompson. "Pre-cropping with canola decreased Pratylenchus thornei populations, arbuscular mycorrhizal fungi, and yield of wheat." Crop and Pasture Science 61, no. 5 (2010): 399. http://dx.doi.org/10.1071/cp09345.
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Root-lesion nematode (Pratylenchus thornei) significantly reduces wheat yields in the northern Australian grain region. Canola is thought to have a ‘biofumigation’ potential to control nematodes; therefore, a field experiment was designed to compare canola with other winter crops or clean-fallow for reducing P. thornei population densities and improving growth of P. thornei-intolerant wheat (cv. Batavia) in the following year. Immediately after harvest of the first-year crops, populations of P. thornei were lowest following various canola cultivars or clean-fallow (1957–5200 P. thornei/kg dry soil) and were highest following susceptible wheat cultivars (31 033–41 294/kg dry soil). Unexpectedly, at planting of the second-year wheat crop, nematode populations were at more uniform lower levels (<5000/kg dry soil), irrespective of the previous season’s treatment, and remained that way during the growing season, which was quite dry. Growth and grain yield of the second-year wheat crop were poorest on plots previously planted with canola or left fallow due to poor colonisation with arbuscular mycorrhizal (AM) fungi, with the exception of canola cv. Karoo, which had high AM fungal colonisation and low wheat yields. There were significant regressions between growth and yield parameters of the second-year wheat and levels of AMF following the pre-crop treatments. Thus, canola appears to be a good crop for reducing P. thornei populations, but AM fungal-dependence of subsequent crops should be considered, particularly in the northern Australian grain region.
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Doyle, AD, RW McLeod, PTW Wong, SE Hetherington, and RJ Southwell. "Evidence for the involvement of the root lesion nematode Pratylenchus thornei in wheat yield decline in northern New South Wales." Australian Journal of Experimental Agriculture 27, no. 4 (1987): 563. http://dx.doi.org/10.1071/ea9870563.
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Factors responsible for a decline in wheat yields in some paddocks in the Gunnedah (northern New South Wales) area were investigated in a series of field experiments. Yield decline is not apparent on soils cultivated for less than 10 years, and barley and sorghum crops are not affected. Plant nutrition apparently is not a major factor in the decline, because, although there was a small response to zinc application in 1 experiment, wheat yields were not significantly increased by the application of N, P, K, Cu, Mg, B, Mn, Mo or S in a paddock where the yield of wheat was half that of the surrounding barley crop. Fumigation of the soil with methyl bromide increased wheat cv. Timgalen yield by 78% to equal that of barley cv. Clipper in a second experiment. Large numbers of root lesion nematodes (Pratylenchus thornei) were associated with unfumigated wheat plots, with smaller numbers present on barley plots. In a third experiment, the grain yields of all of the 9 cereal genotypes tested were increased when sown with 4 kg/ha of aldicarb. The relative yield increase associated with aldicarb showed good correlation with the reputed tolerance of the genotypes to P. thornei. Pratylenchus thornei occurred to a depth of 120 cm. Aldicarb did not affect P. thornei numbers below 15 cm, while methyl bromide controlled P. thornei to depths of 30-90 cm. Aldicarb virtually eliminated P. thornei from the surface 10 cm of soil, but had no effect on the incidence of the fungal diseases common root rot (Bipolaris sorokiniana) or crown rot (Fusarium graminearum). Soil fumigation with methyl bromide controlled B. sorokiniana and F. graminearum as well as P. thornei and gave yields 9% higher than did treatment with aldicarb. In another experiment, ethylene dibromide (2.7-10.8 L/ha) had no consistent effect on the yield of wheat or numbers of P. thornei while terbufos (0.6 and 1.2 kg/ha) gave a small reduction in P. thornei numbers and a small increase in yield. These data indicate that P. thornei is at least partially responsible for wheat yield decline in parts of northern New South Wales.
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Mokrini, Fouad, Lieven Waeyenberge, Nicole Viaene, Fouad Abbad Andaloussi, and Maurice Moens. "The β-1,4-endoglucanase gene is suitable for the molecular quantification of the root-lesion nematode, Pratylenchus thornei." Nematology 16, no. 7 (2014): 789–96. http://dx.doi.org/10.1163/15685411-00002808.
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A real-time quantitative PCR assay was developed for the accurate detection and quantification of the root-lesion nematode, Pratylenchus thornei. A qPCR primer set, including two primers and a probe, was designed based on the sequence of the β-1,4-endoglucanase gene. The assay was optimised by using the primers with SYBR green I dye and setting the qPCR program to different annealing temperatures ranging from 62 to 69°C. Based on the Ct values, we retained the program with an annealing temperature of 69°C. The specificity of the qPCR assay including the probe was confirmed by the lack of amplification of DNA from 47 populations belonging to 15 other Pratylenchus species and nine isolates from P. thornei. The assay was very sensitive as it was able to detect a single individual of P. thornei, even when mixed with up to 80 individuals of P. penetrans. DNA was extracted from exactly 80 P. thornei individuals. A dilution series from this DNA resulted in a standard curve showing a highly significant linearity between the Ct values and the dilution rates (; slope = −3.38; ). The qPCR assay developed in this study proved to be specific and sensitive, thus providing a fast and accurate tool for detection and quantification of this pathogen during research, as well as for diagnostic labs.
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Thompson, J. P., and N. P. Seymour. "Inheritance of resistance to root-lesion nematode (Pratylenchus thornei) in wheat landraces and cultivars from the West Asia and North Africa (WANA) region." Crop and Pasture Science 62, no. 1 (2011): 82. http://dx.doi.org/10.1071/cp10309.
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The root-lesion nematode Pratylenchus thornei causes substantial loss to bread wheat production in the northern grain region of Australia and other parts of the world. West Asia and North Africa (WANA) wheat accessions with partial resistance to P. thornei were analysed for mode of inheritance in a half-diallel crossing design of F1 hybrids (10 parents) and F2 populations (7 parents). General combining ability was more important than specific combining ability as indicated by components of variance ratios of 0.93 and 0.95 in diallel ANOVA of the F1 and F2 generations, respectively. General combining ability values of the ‘resistant’ parents were predictive of the mean nematode numbers of their progeny in crosses with the susceptible Australian cv. Janz at the F1 (R2 = 0.86, P < 0.001, 8 crosses), F2 (R2 = 0.83, P < 0.001, 9 populations) and F∞ (R2 = 0.71, P < 0.05, 5 doubled-haploid populations). The F2 and F∞ populations showed relatively continuous distributions. Heritability was 0.68 for F2 populations in the half-diallel of resistant parents and 0.82–0.92 for 5 ‘resistant’ parent/Janz doubled-haploid populations (narrow-sense heritability on a line mean basis). The results indicate polygenic inheritance of P. thornei resistance with a minimum of from 2 to 6 genes involved in individual F∞ populations of 5 resistant parents crossed with Janz. Morocco 426 and Iraq 43 appear to be the best of the parents tested for breeding for resistance to P. thornei. None of the P. thornei-resistant WANA accessions was resistant to Pratylenchus neglectus.
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Nombela, Gloria, and Dolores Romero. "Host response to Pratylenchus thornei of a wheat line carrying the Cre2 gene for resistance to Heterodera avenae." Nematology 1, no. 4 (1999): 381–88. http://dx.doi.org/10.1163/156854199508379.
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Abstract The introgression wheat line H93-8 (bearer of the gene Cre2 for resistance to Heterodera avenae) was evaluated for response to Pratylenchus thornei and H. avenae in a 5-month field experiment in comparison with its progenitors and other wheat cultivars. Previously, the response of H93-8 to P. thornei was compared to other T. aestivum cultivars under controlled conditions in a 2 month laboratory assay. Line H93-8 was resistant to P. thornei under controlled conditions: after two months the nematode populations were less than half that in cv. Anza and H93-8 plants while they clearly increased in cvs Loros and Rinconada. Under field conditions, fewer H. avenae females were found in H93-8 and its wild donor Aegilops ventricosa than in the H10-15 wheat parent and the bridge species T. turgidum. No significant differences in the number of H. avenae indicated similarity between the resistance conferred by Cre2 in line H93-8 and that regulated by Cre1 in cv. Loros. The parental line H10-15 hosted nearly half as many females as the susceptible control Capa, but as many as Rinconada. The variability observed in host responses to P. thornei when analysed under controlled conditions or in the field, makes it advisable to carry out both kinds of studies for the assessment of resistant cultivars. Results in the field trial suggest that approximately 5 months is the most secure time period to detect real differences in response to P. thornei due to penetration rates and reproduction of these nematodes depending on the line or variety. During the first 2.5 months, the population of P. thornei increased quickly in H93-8 but, at ear emergence, this line hosted similar numbers to its parents, Ae. ventricosa and H10-15. T. turgidum was clearly the most susceptible host in the field to P. thornei. The controls Rinconada and Loros were the least susceptible among the plants tested in the field but, at the end of the experiment, they were significantly different only from T. turgidum. So, it was possible to detect a differential host response or different levels of susceptibility, but none of the tested cultivars or wheat lines was clearly resistant to P. thornei under field conditions. Finally, a negative correlation between H. avenae and P. thornei populations was detected in the field after 5 months only on cv. Loros. Die Reaktion einer Weizenlinie mit dem Cre2-Gen fur Resistenz gegen Heterodera avenae auf Pratylenchus thornei - Die Weizen-Ingressionsline H93-8 (Trager des Gens Cre2 fur Resistenz gegen Heterodera avenae) wurde in einem funfmonatigen Feldversuch auf ihre Reaktion gegenuber Pratylenchus thornei gepruft und mit ihren Vorfahren sowie mit anderen Weizensorten verglichen. Vorher war die Reaktion von H93-8 auf P. thornei in einem zweimonatigen Laborversuch unter kontrollierten Bedingungen mit anderen Sorten von Triticum aestivum verglichen worden. Die Linie H93-8 war unter kontrollierten Bedingungen resistent gegen P. thornei: nach zwei Monaten waren die Nematodenpopulationen an H93-8 und der Sorte Anza um mehr als die Halfte geringer als die inokulierte Nematodenanzahl, wahrend sie an den Sorten Loros und Rinconada deutlich zugenommen hatten. Unter Feldbedingungen wurden an H93-8 und dem wilden Spender Aegilops ventricosa weniger Weibchen von H. avenae gefunden als an dem H10-15 Weizenelter und der Bruckenart T. turgidum. Das Fehlen deutlicher Unterschiede in der Anzahl der Weibchen von H. avenae wies auf eine Ahnlichkeit zwischen der durch Cre2 in die Linie H93-8 ubertragenen und der durch Cre1 regulierten Resistenz in der Sorte Loros hin. Die elterliche Linie H10-15 beherbergte nur etwa halb soviele Weibchen wie die anfallige Capa, doch genau soviele wie Rinconada. Die unter kontrollierten Bedingungen sowie im Feldversuch beobachtete Variabilitat der Wirtsreaktionen gegenuber P. thornei lasst es ratsam erscheinen, bei der Bewertung der Resistenz beide Arten von Versuchen durchzufuhren. Die Ergebnisse des Feldversuches zeigen, dass etwa funf Monate der sichersten Zeitraum ist, um wirkliche Unterschiede in der Wirtsreaktion auf P. thornei zu finden, da die Einwanderungs- und Vermehrungstraten je nach Linie und Sorte unterschiedlich sein konnen. Wahrend der ersten 2,5 Monate stieg die Population von P. thornei in H93-8 schnell an, aber beim Ahrenschieben beherbergte diese Linie ahnliche Anzahlen wie ihre Eltern Ae. ventricosa und H10-15. T. turgidum war im Feld deutlich der anfalligste Wirt fur P. thornei. Die Kontrollen Rinconada und Loros waren die am wenigsten anfalligen der im Feldversuch gepruften Pflanzen, doch bestanden bei Versuchsende nur zu T. turgidum signifikante Unterschiede. Es war also moglich, eine Differentialwirtreaktion oder unterschiedliche Grade der Anfalligkeit zu entdecken, jedoch war keine der gepruften Sorten oder Weizenlinen unter Feldbedingungen deutlich resistent gegen P. thornei . Eine negative Korrelation zwischen den Populationen von H. avenae und P. thornei wurde im Feld nach funf Monaten nur an der Sorte Loros gefunden.
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Smiley, Richard W., Jennifer A. Gourlie, Guiping Yan, and Karl E. L. Rhinhart. "Resistance and Tolerance of Landrace Wheat in Fields Infested with Pratylenchus neglectus and P. thornei." Plant Disease 98, no. 6 (June 2014): 797–805. http://dx.doi.org/10.1094/pdis-10-13-1069-re.
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Pratylenchus neglectus and P. thornei reduce wheat yields in the Pacific Northwest of the United States. Resistant landrace cultivars have been identified using controlled environments. Field resistance and tolerance characteristics were compared over 3 years and two locations for four spring wheat cultivars: the susceptible ‘Alpowa’ and ‘Louise’ and the resistant landraces AUS28451 and Persia 20. Proportions and densities of P. neglectus and P. thornei differed across seasons and locations. Resistance was evaluated by comparing preplant and postharvest densities of nematodes in soil. Tolerance was evaluated by comparing grain yield and grain quality in plots treated or untreated by the nematicide aldicarb. Alpowa was susceptible and intolerant, Louise was susceptible and moderately tolerant, AUS28451 was resistant and intolerant, and Persia 20 was moderately susceptible and moderately intolerant. The species dominance shifted from P. neglectus to P. thornei in one field over a period of 3 years in apparent response to cultivars and crops planted. Estimates of economic loss caused by Pratylenchus spp. ranged from $8 to $20/ha. Economic benefits appear to be achievable by developing a spring wheat genotype with tolerance plus resistance, such as with a cross between AUS28451 and Louise.
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Owen, Kirsty J., Timothy G. Clewett, Kerry L. Bell, and John P. Thompson. "Cereal and Pulse Crops with Improved Resistance to Pratylenchus thornei Are Needed to Maximize Wheat Production and Expand Crop Sequence Options." Agronomy 12, no. 3 (February 25, 2022): 573. http://dx.doi.org/10.3390/agronomy12030573.
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In the subtropical grain region of eastern Australia, two experiments were conducted, one initially with 2490 P. thornei/kg soil, the other with 8150 P. thornei/kg soil at 0–0.9 m soil depth. We determined the effect of P. thornei, residual from a weed-free fallow and pre-cropping with several cultivars each of barley (Hordeum vulgare), faba bean (Vicia faba), chickpea (Cicer arietinum), and wheat (Triticum aestivum) (Phase 1), on the growth of wheat cultivars with intolerance or tolerance to P. thornei (Phase 2). Pratylenchus thornei substantially increased after growing all cultivars of the Phase 1 faba bean, barley, and most cultivars of chickpea and wheat, and decreased after two moderately resistant wheat cultivars and the fallow treatment. The biomass of the Phase 2 tolerant cultivar ranged from 5070 to 6780 kg/ha and the intolerant cultivar 1020 to 4740 kg/ha. There was a negative linear relationship between P. thornei population densities and biomass of the Phase 2 intolerant cultivar but not of the tolerant cultivar. Growers are at risk of financial loss because they are restricted in their choice of crops to reduce damaging population densities of P. thornei. The development of resistant and tolerant crop genotypes can maximize production in P. thornei-affected farming systems.
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Thompson, J. P., and M. I. Haak. "Resistance to root-lesion nematode (Pratylenchus thornei) in Aegilops tauschii Coss., the D-genome donor to wheat." Australian Journal of Agricultural Research 48, no. 5 (1997): 553. http://dx.doi.org/10.1071/a96167.
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Root-lesion nematode (Pratylenchus thornei Sher and Allen) causes substantial loss in yield of wheat in eastern Australia. Central Asian accessions of Aegilops tauschii Coss. were tested to find new sources of resistance to P. thornei for use in wheat-breeding programs. Ae. tauschii (2n = 14, DD genome) is one of the wild progenitors of wheat, Triticum aestivum L. (2n = 42, AABBDD genomes). Resistance was determined by nematode reproduction in the plant roots during 16 weeks of growth in pots in a glasshouse. Thirty-nine of 244 accessions of Ae. tauschii tested in 2 replicated experiments had lower numbers of nematodes than GS50a, a partially resistant line of wheat used as a resistance standard. Resistance to P. thornei was present in accessions of most taxonomic groups within Ae. tauschii, i.e. Ae. tauschii subsp. strangulata (Eig) Tzvel., and Ae. tauschii subsp. tauschii var. typica L. and var. meyeri (Griseb.) Tzvel. Resistance was most common in subsp. strangulata with 20 out of 40 strangulata accessions in the resistant group and none in a highly susceptible group of 43 accessions. Accessions of var. meyeri with the Cre3 gene for effective resistance to cereal cyst nematode (Heterodera avenae Woll.) were also resistant to P. thornei. The results indicate that several resistances to P. thornei are present in Ae. tauschii subspecies and varieties, which could be introgressed into cultivated wheat to help control P. thornei and increase farm profits.
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Castillo, Pablo, María P. Mora-Rodríguez, Juan A. Navas-Cortés, and Rafael M. Jiménez-Díaz. "Interactions of Pratylenchus thornei and Fusarium oxysporum f. sp. ciceris on Chickpea." Phytopathology® 88, no. 8 (August 1998): 828–36. http://dx.doi.org/10.1094/phyto.1998.88.8.828.
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Fusarium oxysporum f. sp. ciceris and the root-lesion nematode Pratylenchus thornei coinfect chickpeas in southern Spain. The influence of root infection by P. thornei on the reaction of Fusarium wilt-susceptible (CPS 1 and PV 61) and wilt-resistant (UC 27) chickpea cultivars to F. oxysporum f. sp. ciceris race 5 was investigated under controlled and field conditions. Severity of Fusarium wilt was not modified by coinfection of chickpeas by P. thornei and F. oxysporum f. sp. ciceris, in simultaneous or sequential inoculations with the pathogens. Root infection with five nematodes per cm3 of soil and 5,000 chlamydospores per g of soil of the fungus resulted in significantly higher numbers of propagules of F. oxysporum f. sp. ciceris with the wilt-susceptible cultivar CPS 1, but not with the wilt-resistant one. However, infection with 10 nematodes per cm3 of soil significantly increased root infection by F. oxysporum f. sp. ciceris in both cultivars, irrespective of fungal inoculum densities (250 to 2,000 chlamydospores per g of soil). Plant growth was significantly reduced by P. thornei infection on wilt-susceptible and wilt-resistant chickpeas in controlled and field conditions, except when shorter periods of incubation (45 days after inoculation) were used under controlled conditions. Severity of root necrosis was greater in wilt-susceptible and wilt-resistant cultivars when nematodes were present in the root, irrespective of length of incubation time (45 to 90 days), densities of nematodes (5 and 10 nematodes per cm3 of soil), fungal inocula, and experimental conditions. Nematode reproduction on the wilt-susceptible cultivars, but not on the wilt-resistant one, was significantly increased by F. oxysporum f. sp. ciceris infections under controlled and field conditions.
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Thompson, J. P., M. M. O'Reilly, and T. G. Clewett. "Resistance to the root-lesion nematode Pratylenchus thornei in wheat landraces and cultivars from the West Asia and North Africa (WANA) region." Crop and Pasture Science 60, no. 12 (2009): 1209. http://dx.doi.org/10.1071/cp09159.
Full textAbstract:
Resistance to the root-lesion nematode Pratylenchus thornei was sought in wheat from the West Asia and North Africa (WANA) region in the Watkins Collection (148 bread and 139 durum wheat accessions) and the McIntosh Collection (59 bread and 43 durum wheat accessions). It was considered that landraces from this region, encompassing the centres of origin of wheat and where P. thornei also occurs, could be valuable sources of resistance for use in wheat breeding. Resistance was determined by number of P. thornei/kg soil after the growth of the plants in replicated glasshouse experiments. On average, durum accessions produced significantly lower numbers of P. thornei than bread wheat accessions in both the Watkins and McIntosh Collections. Selected accessions with low P. thornei numbers were re-tested and 13 bread wheat and 10 durum accessions were identified with nematode numbers not significantly different from GS50a, a partially resistant bread wheat line used as a reference standard. These resistant accessions, which originated in Iran, Iraq, Syria, Egypt, Sudan, Morocco, and Tunisia, represent a resource of resistance genes in the primary wheat gene pool, which could be used in Australian wheat breeding programs to reduce the economic loss from P. thornei.
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Nicol, Julie M., and Ivan Ortiz-Monasterio. "Effects of the root-lesion nematode, Pratylenchus thornei, on wheat yields in Mexico." Nematology 6, no. 4 (2004): 485–93. http://dx.doi.org/10.1163/1568541042665223.
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Abstract Tolerance and resistance to P. thornei of seven CIMMYT-derived cultivars of wheat (Triticum aestivum), selected on soil naturally infested by Pratylenchus thornei and released from 1960-1997, were evaluated under optimum and limited irrigation conditions in northwestern Mexico. Replicated trials were grown in a naturally infested site in two seasons. Differences in yield, agronomic traits and nematode numbers were recorded in paired field plots, untreated or fumigated with dazomet to control nematodes. With optimum irrigation the nematode did not affect wheat yield but, with limited irrigation where plants were under water-stress, yield loss of all cultivars was comparable to that of the intolerant, susceptible control cv. Warigal (29%). There was a significant negative linear relationship (Y = –3.69 x + 3117) between initial nematode density (x) and grain yield (Y) under limited irrigation. None of these cultivars was resistant and post-harvest P. thornei populations had increased from three to 15 times the initial estimates. There was no relationship between date of release of cultivars and their responses to the nematode. There is a need for sources of resistance to be identified and incorporated into the germplasm.
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Linsell, Katherine Joanne, Ian Timothy Riley, Kerrie Ann Davies, and Klaus Herbert Oldach. "Characterization of Resistance to Pratylenchus thornei (Nematoda) in Wheat (Triticum aestivum): Attraction, Penetration, Motility, and Reproduction." Phytopathology® 104, no. 2 (February 2014): 174–87. http://dx.doi.org/10.1094/phyto-12-12-0345-r.
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Lines from a cross between two wheat (Triticum aestivum) cultivars with contrasting resistance phenotypes to Pratylenchus thornei (Nematoda) were investigated to determine the stage at which resistance occurs. Host resistance was examined at nematode attraction to and penetration of roots and nematode motility, maturation, and reproduction within roots. There was no significant difference in the rate at which P. thornei was attracted toward or penetrated resistant or susceptible roots. However, suppression of migration, juvenile maturation, and reproduction in and near resistant roots was evident, suggesting that resistance acts post penetration. No preferential root penetration zone was observed in contrast to other studies. The inhibitory compounds from resistant wheat plants appeared to be constitutively expressed and water soluble because nematode migration was suppressed in roots and root exudates of unchallenged seedlings. The effects of these compounds were reversible and affected P. thornei but not P. neglectus. Apart from migration, nematode multiplication was greatly inhibited by resistance because only a few juveniles (10%) developed past stage three in roots of resistant compared with susceptible plants. Earlier in the life cycle, egg deposition and hatch of P. thornei were also significantly reduced in resistant roots and root exudates, suggesting the presence of hatching inhibitors.
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Owen, K. J., T. G. Clewett, K. L. Bell, and J. P. Thompson. "Wheat biomass and yield increased when populations of the root-lesion nematode (Pratylenchus thornei) were reduced through sequential rotation of partially resistant winter and summer crops." Crop and Pasture Science 65, no. 3 (2014): 227. http://dx.doi.org/10.1071/cp13295.
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The root-lesion nematode, Pratylenchus thornei, can reduce wheat yields by >50%. Although this nematode has a broad host range, crop rotation can be an effective tool for its management if the host status of crops and cultivars is known. The summer crops grown in the northern grain region of Australia are poorly characterised for their resistance to P. thornei and their role in crop sequencing to improve wheat yields. In a 4-year field experiment, we prepared plots with high or low populations of P. thornei by growing susceptible wheat or partially resistant canaryseed (Phalaris canariensis); after an 11-month, weed-free fallow, several cultivars of eight summer crops were grown. Following another 15-month, weed-free fallow, P. thornei-intolerant wheat cv. Strzelecki was grown. Populations of P. thornei were determined to 150 cm soil depth throughout the experiment. When two partially resistant crops were grown in succession, e.g. canaryseed followed by panicum (Setaria italica), P. thornei populations were <739/kg soil and subsequent wheat yields were 3245 kg/ha. In contrast, after two susceptible crops, e.g. wheat followed by soybean, P. thornei populations were 10 850/kg soil and subsequent wheat yields were just 1383 kg/ha. Regression analysis showed a linear, negative response of wheat biomass and grain yield with increasing P. thornei populations and a predicted loss of 77% for biomass and 62% for grain yield. The best predictor of wheat yield loss was P. thornei populations at 0–90 cm soil depth. Crop rotation can be used to reduce P. thornei populations and increase wheat yield, with greatest gains being made following two partially resistant crops grown sequentially.
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Zwart, R. S., J. P. Thompson, J. G. Sheedy, and J. C. Nelson. "Mapping quantitative trait loci for resistance to Pratylenchus thornei from synthetic hexaploid wheat in the International Triticeae Mapping Initiative (ITMI) population." Australian Journal of Agricultural Research 57, no. 5 (2006): 525. http://dx.doi.org/10.1071/ar05177.
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Root-lesion nematode (Pratylenchus thornei) is a serious pathogen of wheat in many countries. The International Triticeae Mapping Initiative (ITMI) population of recombinant inbred lines (RILs) was assessed for resistance to P. thornei to determine the chromosome locations of the resistance genes. The ITMI population is derived from a cross between the resistant synthetic hexaploid wheat W-7984 and a susceptible bread wheat cultivar Opata 85. Two years of phenotypic data for resistance to P. thornei were obtained in replicated glasshouse trials. Quantitative trait locus (QTL) analysis was performed using available segregation and map data for 114 RILs. A QTL on chromosome 6DS showed consistent effects for reduced nematode numbers (partial resistance) across years and accounted for 11% and 23% of the phenotypic variation. A second QTL for P. thornei resistance on chromosome 2BS accounted for an additional 19% and 5%. Restriction fragment length polymorphism (RFLP) and simple sequence repeat (SSR) markers associated with the QTLs are physically located in regions rich in major genes at the distal ends of the short chromosome arms of 6D and 2B. SSR markers with potential for marker-assisted selection of P. thornei resistance effective in different genetic backgrounds have been identified.
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Navas-Cortés, Juan, Blanca Landa, Nicola Vovlas, Gracia Liébanas, Pablo Castillo, Juan Palomares-Rius, and Sergei Subbotin. "Description of Pratylenchus hispaniensis n. sp. from Spain and considerations on the phylogenetic relationship among selected genera in the family Pratylenchidae." Nematology 12, no. 3 (2010): 429–51. http://dx.doi.org/10.1163/138855409x12559479585043.
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AbstractA new amphimictic species, Pratylenchus hispaniensis n. sp., parasitising the roots of gum cistus in Andújar (Jaén), southern Spain, is described. The new species is characterised by the presence of numerous males and by the female having a lip region with three annuli, a divided face, a robust stylet (14.5-17.0 μm) with rounded knobs, lateral fields with four lines, V = 80-84, a round spermatheca full of sperm, well developed post-vulval uterine sac and an obliquely truncate tail with irregularly annulated terminus. Morphologically this species is related to P. bhatti, P. kralli, P. mediterraneus, P. pseudofallax and P. thornei. A phenetic study of the 25 most useful diagnostic morphological and allometric characters for Pratylenchus species was done using multivariate factor and linear discriminant analyses. In the factor analysis the first seven factors accounted for 71.1% of the total variance of the characters selected. These factors were related to female tail, pharyngeal overlap, reproductive behaviour, stylet length, L/post-vulval uterine sac ratio, body length and number of lip annuli. Discriminant analysis differentiated Pratylenchus spp. from the three valid species of Zygotylenchus. The results of the phylogenetic analysis based on sequences of the D2-D3 expansion regions of 28S, partial 18S and ITS rRNA genes confirmed the close relationship of P. hispaniensis n. sp. with P. mediterraneus and inferred molecular affinity with P. brzeskii, P. neglectus and P. thornei, in spite of variation in the position of P. hispaniensis n. sp. in the clades. Additional phylogenetic analyses based on the same sets of sequences for P. hispaniensis n. sp., Zygotylenchus guevarai and other Pratylenchidae indicated that Pratylenchus includes several paraphyletic lineages; however, likelihood tests did not reject monophyly of the genus. The inclusion of Pratylenchus, Zygotylenchus, Hirschmanniella, Nacobbus and Apratylenchus in Pratylenchidae was supported.
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Hajihassani, Abolfazl, Richard W. Smiley, and Farahnaz Jahanshahi Afshar. "Effects of Co-inoculation with Pratylenchus thornei and Fusarium culmorum on Growth and Yield of Winter Wheat." Plant Disease 97, no. 11 (November 2013): 1470–77. http://dx.doi.org/10.1094/pdis-02-13-0168-re.
Full textAbstract:
Growth and yield of winter wheat are suppressed by Pratylenchus thornei and by Fusarium culmorum. Many fields in cereal production regions throughout the world are infested by both pathogens. We evaluated effects of one or both pathogens on winter wheat growth, grain yield, and disease parameters at heading and harvest stages over 2 years in inoculated, rainfed pots incubated outdoors. P. thornei nematodes were inoculated at 1, 2, or 4 nematodes/g of soil and F. culmorum was added as colonized millet seed at 0.65 g/kg of soil. At harvest, compared with the noninoculated control, the high rate of P. thornei reduced (P < 0.05) plant height, shoot weight, root weight, and grain yield by 19, 17, 48, and 31%, respectively. F. culmorum alone reduced these parameters by 15, 16, 22, and 22%, respectively. Co-inoculations caused reductions of 27, 38, 61, and 63%, respectively. The reproductive rate of P. thornei was not greatly affected by co-inoculation with F. culmorum. Disease severity ratings at both plant growth stages became amplified as the nematode density was increased, and were much greater in the presence of both pathogens. Effects of co-inoculation on grain yield were slightly greater than predicted by additive effects of the individual pathogens, suggesting a synergistic effect on yield depression.
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Thompson, John P., and Timothy G. Clewett. "Investigating the Impact of Root-Lesion Nematodes (Pratylenchus thornei) and Crown Rot (Fusarium pseudograminearum) on Diverse Cereal Cultivars in a Conservation Farming System." Agronomy 11, no. 5 (April 28, 2021): 867. http://dx.doi.org/10.3390/agronomy11050867.
Full textAbstract:
In two experiments on a farm practicing conservation agriculture, the grain yield of a range of wheat cultivars was significantly (p < 0.001) negatively related to the post-harvest population densities of Pratylenchus thornei in the soil profile to 45 cm depth. In a third and fourth experiment with different rotations, methyl bromide fumigation significantly (p < 0.05) decreased (a) a low initial population density of P. thornei in the soil profile to 90 cm depth and (b) a high initial population of P. thornei to 45 cm depth, and a medium level of the crown rot fungus, Fusarium pseudograminearum, at 0–15 cm depth to a low level. For a range of wheat and durum cultivars, grain yield and response to fumigation were highly significantly (p < 0.001) related to (a) the P. thornei tolerance index of the cultivars in the third experiment, and (b) to both the P. thornei tolerance index and the crown rot resistance index in the fourth experiment. In the latter, grain yield was significantly (p < 0.001) positively related to biomass at anthesis and negatively related to percentage whiteheads at grain fill growth stage. One barley cultivar was more tolerant to both diseases than the wheat and durum cultivars. Crop rotation, utilizing crop cultivars resistant and tolerant to both P. thornei and F. pseudograminearum, is key to success for conservation farming in this region.
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Jatav, Rajbabbar. "Reaction of Pratylenchus thornei and Rhizoctonia bataticola in Chickpea Genotypes." International Journal of Pure & Applied Bioscience 6, no. 3 (June 30, 2018): 19–24. http://dx.doi.org/10.18782/2320-7051.6705.
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Whish, J. P. M., J. P. Thompson, T. G. Clewett, J. L. Lawrence, and J. Wood. "Pratylenchus thornei populations reduce water uptake in intolerant wheat cultivars." Field Crops Research 161 (May 2014): 1–10. http://dx.doi.org/10.1016/j.fcr.2014.02.002.
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CASTILLO, P., R. M. JIMENEZ-DIAZ, A. GOMEZ-BARCINA, and N. VOVLAS. "Parasitism of the root-lesion nematode Pratylenchus thornei on chickpea." Plant Pathology 44, no. 4 (August 1995): 728–33. http://dx.doi.org/10.1111/j.1365-3059.1995.tb01697.x.
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Thompson, John P., and Timothy G. Clewett. "Impacts of Root-Lesion Nematode (Pratylenchus thornei) on Plant Nutrition, Biomass, Grain Yield and Yield Components of Susceptible/Intolerant Wheat Cultivars Determined by Nematicide Applications." Agronomy 11, no. 2 (February 6, 2021): 296. http://dx.doi.org/10.3390/agronomy11020296.
Full textAbstract:
Field experiments testing rates of various nematicides, with and without NPZn fertiliser, were analysed to investigate how root-lesion nematode (Pratylenchus thornei) affects growth and yield components of susceptible/intolerant wheat cultivars in a subtropical environment. Plant response to nematode attack was assessed by regression and principal components analyses of various plant parameters at different crop development stages, in relation to different nematode population densities in the roots and root-zone soil. Reduction in P. thornei population densities by nematicides resulted in increased numbers of tillers, plant biomass, N and P concentrations and uptakes, numbers of spikes and kernels, and grain yield. Grain yield was strongly correlated with number of kernels, biomass and number of spikes, and negatively correlated with number of P. thornei in the root-zone soil at stem elongation. This study showed that P. thornei damage to roots decreased wheat yield through limiting N and P concentrations and uptakes in plant tops causing poor growth that commenced early and continued through the life of the crop. Genetic, environmental and management factors that reduce population densities of P. thornei, and decrease the impact of the nematodes starting in early crop growth, will greatly increase spike and kernel numbers and grain yield.
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Taylor, S. P., V. A. Vanstone, A. H. Ware, A. C. McKay, D. Szot, and M. H. Russ. "Measuring yield loss in cereals caused by root lesion nematodes (Pratylenchus neglectus and P. thornei) with and without nematicide." Australian Journal of Agricultural Research 50, no. 4 (1999): 617. http://dx.doi.org/10.1071/a98103.
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Yield loss caused by root lesion nematodes (Pratylenchus neglectus and P. thornei) was measured using the nematicide aldicarb (Temik 150GTM) or by correlating yield with initial or final nematode densities. In 1996, rotation trials (1 P. neglectus and 1 P. thornei) were established with susceptible and moderately resistant wheat varieties and resistant barley and triticale varieties. An intolerant oat variety (cv. Echidna) was planted over all plots in 1997. Nematode densities were 90% (P. neglectus) or 95% (P. thornei) lower in oat plots following the resistant triticale (cv. Tahara) relative to the susceptible wheat (cv. Machete). In 1997, a significant, negative correlation between both initial and final nematode density and yield was obtained. In wheat variety trials (3 sites) in 1997, a significant, negative correlation was also obtained between mean variety yield and mean final P. neglectus density or mean P. neglectus multiplication rate. Yield loss of up to 20% was calculated from the regression. In all trials, cereal varieties that were more resistant were also more tolerant. In 1996, aldicarb rate trials (1 P. neglectus and 1 P. thornei) were established to assess the affect of rate and timing of aldicarb application on yield of 2 susceptible/intolerant wheat varieties (cvv. Machete and Janz). Lower rates of aldicarb (≤1.5 kg a.i./ha) gave inconsistent nematode control and did not significantly increase yield. Rates ≥2.5 kg a.i./ha reduced nematode densities by 70–90%, resulting in up to 23% greater yield for Machete. The magnitude of yield loss caused by P. neglectus or P. thornei determined with or without nematicide was similar between trials.
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Toktay, Halil, C. Lynne McIntyre, Julie M. Nicol, Hakan Ozkan, and Halil I. Elekcioglu. "Identification of common root-lesion nematode (Pratylenchus thornei Sher et Allen) loci in bread wheat." Genome 49, no. 10 (October 2006): 1319–23. http://dx.doi.org/10.1139/g06-090.
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Plant parasitic nematodes are a major biotic cause of wheat-yield loss in temperate wheat-growing regions. A major strategy to develop resistance to root-lesion nematodes (RLNs) in wheat is to assess and then exploit their natural genetic variation. This study examines RLN (Pratylenchus thornei) resistance in 1 Middle Eastern landrace (AUS4930 7.2) and 1 synthetic hexaploid wheat, CROC_1/AE.SQUARROSA (224)//OPATA (CROC), using F2 and F9 populations generated by crossing AUS4930 7.2 and CROC with the susceptible cultivar Pastor, and inoculating these crosses with P. thornei in greenhouse trials. Wheat microsatellite markers linked to previously identified quantitative trait loci (QTLs) for resistance to P. thornei and P. neglectus were used to screen both populations. In the AUS4930 7.2 × Pastor population, resistance loci on chromosomes 1B, 2B, and 6D were detected. Similarly, in the CROC × Pastor population, 2 resistance loci, located on chromosomes 1B and 3B, were identified. Interestingly, a resistance locus located on chromosome 6D was not detected. More detailed mapping is required in these 2 populations, developed using new RLN resistance sources, to determine whether the QTLs identified on these chromosomes are the same, are allelic, or are linked to different resistance loci from those previously identified, and to determine whether these 2 sources contain other novel resistance loci.
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Yan, Guiping, Richard W. Smiley, Patricia A. Okubara, Andrea Skantar, Sandra A. Easley, Jason G. Sheedy, and Alison L. Thompson. "Detection and Discrimination of Pratylenchus neglectus and P. thornei in DNA Extracts from Soil." Plant Disease 92, no. 11 (November 2008): 1480–87. http://dx.doi.org/10.1094/pdis-92-11-1480.
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A species-specific polymerase chain reaction (PCR) method was developed to detect and identify the root-lesion nematodes Pratylenchus neglectus and P. thornei from soil. A primer set was designed from Pratylenchus 28S rRNA gene sequences of the D3 expansion domain. Primer specificity was confirmed with 23 isolates of 15 nematode species and other plant-parasitic and non-plant-parasitic nematodes typically present in the soil communities, and with six fungal species commonly associated with wheat root rot. DNA obtained using a commercially available kit and a method developed in our laboratory gave comparable amplification. PCR conditions were optimized and the two species were differentiated by PCR products of 144 bp for P. neglectus and 288 bp for P. thornei. With this assay, we detected a single juvenile in 1 g of sterile, inoculated soil. Examination of 30 field soil samples revealed that this method was applicable to a range of soils naturally infested with these two pathogens in Oregon. This PCR-based method is rapid, efficient, and reliable, does not require expertise in nematode taxonomy and morphology, and could be used as a rapid diagnostic tool for commercial and research applications for disease forecasting and management.
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Farsi, M., VA Vanstone, JM Fisher, and AJ Rathjen. "Genetic variation in resistance to Pratylenchus neglectus in wheat and triticales." Australian Journal of Experimental Agriculture 35, no. 5 (1995): 597. http://dx.doi.org/10.1071/ea9950597.
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The root lesion nematode Pratylenchus neglectus occurs throughout the South Australian cereal belt, where it potentially contributes to yield loss. Genetic material was examined for resistance to P. neglectus, and included 2 susceptible local commercial wheat varieties (Spear, Molineux), 2 derivatives from Spear (RAC 613-27, RAC 613-47), wheat varieties varying in reaction to I? thornei, rye and rye derivatives, triticales, and 1R substitution lines in Chinese Spring. Seeds were surface-sterilised and germinated, and 3-day-old seedlings were inoculated with about 250 larvae and 150 eggs. Plants were grown in pots containing pasteurised soil and transferred to a controlled temperature waterbath at 22 � 1�C. After 7 weeks, nematodes were extracted and counted. A significant difference for the number of nematodes per plant and per gram dry root was found between the 3 main groups of genetic material: the wheat varieties, the substitution lines, and lines with the whole genome of rye (including triticales). The triticales Abacus and Muir showed the lowest number of nematodes (per gram root and per plant). None of the wheat varieties was resistant, so genetic mechanisms conferring resistance or tolerance to P. thornei are not effective against P. neglectus.
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Reen, R. A., J. P. Thompson, T. G. Clewett, J. G. Sheedy, and K. L. Bell. "Yield response in chickpea cultivars and wheat following crop rotations affecting population densities of Pratylenchus thornei and arbuscular mycorrhizal fungi." Crop and Pasture Science 65, no. 5 (2014): 428. http://dx.doi.org/10.1071/cp13441.
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In Australia, root-lesion nematode (RLN; Pratylenchus thornei) significantly reduces chickpea and wheat yields. Yield losses from RLN have been determined through use of nematicide; however, nematicide does not control nematodes in Vertosol subsoils in Australia’s northern grains region. The alternative strategy of assessing yield response, by using crop rotation with resistant and susceptible crops to manipulate nematode populations, is poorly documented for chickpea. Our research tested the effectiveness of crop rotation and nematicide against P. thornei populations for assessing yield loss in chickpea. First-year field plots included canola, linseed, canaryseed, wheat and a fallow treatment, all with and without the nematicide aldicarb. The following year, aldicarb was reapplied and plots were re-cropped with four chickpea cultivars and one intolerant wheat cultivar. Highest P. thornei populations were after wheat, at 0.45–0.6 m soil depth. Aldicarb was effective to just 0.3 m for wheat and 0.45 m for other crops, and increased subsequent crop grain yield by only 6%. Canola, linseed and fallow treatments reduced P. thornei populations, but low mycorrhizal spore levels in the soil after canola and fallow treatments were associated with low chickpea yield. Canaryseed kept P. thornei populations low throughout the soil profile and maintained mycorrhizal spore densities, resulting in grain yield increases of up to 25% for chickpea cultivars and 55% for wheat when pre-cropped with canaryseed compared with wheat. Tolerance indices for chickpeas based on yield differences after paired wheat and canaryseed plots ranged from 80% for cv. Tyson to 95% for cv. Lasseter and this strategy is recommended for future use in assessing tolerance.
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Waeyenberge, Lieven, Alexander Ryss, Maurice Moens, Jorge Pinochet, and Thierry Vrain. "Molecular characterisation of 18 Pratylenchus species using rDNA Restriction Fragment Length Polymorphism." Nematology 2, no. 2 (2000): 135–42. http://dx.doi.org/10.1163/156854100509024.
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AbstractThe RFLP technique was used to establish a reliable diagnostic method for 18 Pratylenchus species: Pratylenchus agilis, P. bolivianus, P. brachyurus, P. coffeae, P. crenatus, P. fallax, P. goodeyi, P. loosi, P. mediterraneus, P. neglectus, P. penetrans, P. pratensis, P. pseudocoffeae, P. scribneri, P. subranjani, P. thornei, P. vulnus and P. zeae. The polymerase chain reaction (PCR) amplified the ITS regions from all species and populations examined and revealed large differences in length, ranging in size from approximately 900 to 1250 bp. The rDNA fragments were digested with five restriction enzymes (CfoI, DdeI, HindIII, HpaII, and PstI). All Pratylenchus species can be differentiated from each other by a combination of at least two enzymes. CfoI differentiated all nematode species with the exception of P. fallax, P. penetrans and P. pseudocoffeae. P. fallax was further separated by a DdeI restriction, and P. pseudocoffeae by a PstI digestion. Intraspecific RFLP were observed. Upon CfoI, DdeI, HindIII, or HpaII digestion, it was possible to separate the three P. coffeae populations studied from each other. La technique RFLP a été utilisée pour créer une méthode fiable de diagnostic pour 18 espèces de Pratylenchus: Pratylenchus agilis, P. bolivianus, P. brachyurus, P. coffeae, P. crenatus, P. fallax, P. goodeyi, P. loosi, P. mediterraneus, P. neglectus, P. penetrans, P. pratensis, P. pseudocoffeae, P. scribneri, P. subranjani, P. thornei, P. vulnus et P. zeae. La réaction de polymérisation en chaîne (PCR) a amplifié les régions de l’ITS pour toutes les espèces et populations étudiées et a mis en évidence de grandes différences dans la taille des gammes de longueur, de 900 à 1250 bp approximativement. Les fragments de rDNA ont été digérés à l’aide de cinq enzymes de restriction (CfoI, DdeI, HindIII, HpaII, and PstI). Toutes les espèces de Pratylenchus ont pu être différenciées les unes des autres par une combinaison d’au moins deux enzymes. CfoI a différencié toutes les espèces à l’exception de P. fallax, P. penetrans et P. pseudocoffeae. P. fallax a été ultérieurement séparé par une restriction DdeI, et P. pseudocoffeae par une digestion PstI. Des RFLP intraspécifiques ont été observés. Par les digestions CfoI, DdeI, HindIII, ou HpaII, il s’est révélé possible de séparer les unes des autres les trois populations étudiées de P. coffeae.
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Smiley, Richard W., Jason G. Sheedy, and Sandra A. Easley. "Vertical Distribution of Pratylenchus spp. in Silt Loam Soil and Pacific Northwest Dryland Crops." Plant Disease 92, no. 12 (December 2008): 1662–68. http://dx.doi.org/10.1094/pdis-92-12-1662.
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Dryland field crops in the Pacific Northwest United States are commonly produced in silt loams infested by the root-lesion nematodes Pratylenchus neglectus and P. thornei. Soils at 30 sites in Oregon were sampled from 0 to 120 cm depth to examine the vertical distribution of these Pratylenchus spp. Both species were distributed through entire soil profiles of all cropping systems. Populations were generally greatest in the surface 30 cm, but sometimes high populations were detected at depths greater than 45 cm. Sampling to 30 cm depth allowed detection of more than 50% of the population in most sites, while sampling to 45 cm depth yielded more than 75% of the population in over 75% of the sites evaluated. Therefore, soil samples should be collected to 30 to 45 cm depth to accurately estimate populations of Pratylenchus spp. in dryland crops produced on silt loams in the Pacific Northwest. Populations of Pratylenchus spp. were found to be related to the most recently planted crop, with populations after barley, after wheat, and during summer fallow being detected in ascending order.
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Thompson, J. P. "Resistance to root-lesion nematodes (Pratylenchus thornei and P. neglectus) in synthetic hexaploid wheats and their durum and Aegilops tauschii parents." Australian Journal of Agricultural Research 59, no. 5 (2008): 432. http://dx.doi.org/10.1071/ar07222.
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Root-lesion nematodes (Pratylenchus thornei Sher and Allen and P. neglectus (Rensch) Filipijev and Schuurmans Stekhoven) cause substantial yield loss to wheat crops in the northern grain region of Australia. Resistance to P. thornei for use in wheat breeding programs was sought among synthetic hexaploid wheats (2n = 6x = 42, AABBDD) produced through hybridisations of Triticum turgidum L. subsp. durum (Desf.) Husn (2n = 4x = 28, AABB) with Aegilops tauschii Coss. (2n = 2x = 14, DD). Resistance was determined for the synthetic hexaploid wheats and their durum and Ae. tauschii parents from the numbers of nematodes in the roots of plants grown for 16 weeks in pots of pasteurised soil inoculated with P. thornei. Fifty-nine (32%) of 186 accessions of synthetic hexaploid wheats had lower numbers of nematodes than Gatcher Selection 50a (GS50a), a partially resistant bread wheat. Greater frequencies of partial resistance were present in the durum parents (72% of 39 lines having lower nematode numbers than GS50a) and in the Ae. tauschii parents (55% of 53 lines). The 59 synthetic hexaploids were re-tested in a second experiment along with their parents. In a third experiment, 11 resistant synthetic hexaploid wheats and their F1 hybrids with Janz, a susceptible bread wheat, were tested and the F1s were found to give nematode counts intermediate between the respective two parents. Synthetic hexaploid wheats with higher levels of resistance resulted from hybridisations where both the durum and Ae. tauschii parents were partially resistant, rather than where only one parent was partially resistant. These results suggest that resistance to P. thornei in synthetic hexaploid wheats is polygenic, with resistances located both in the D genome from Ae. tauschii and in the A and/or B genomes from durum. Five synthetic hexaploid wheats were selected for further study on the basis of (1) a high level of resistance to P. thornei of the synthetic hexaploid wheats and of both their durum and Ae. tauschii parents, (2) being representative of both Australian and CIMMYT (International Maize and Wheat Improvement Centre) durums, and (3) being representative of the morphological subspecies and varieties of Ae. tauschii. These 5 synthetic hexaploid wheats were also shown to be resistant to P. neglectus, whereas GS50a and 2 P. thornei-resistant derivatives were quite susceptible. Results of P. thornei resistance of F1s and F2s from a half diallel of these 5 synthetic hexaploid wheats, GS50a, and Janz from another study indicate polygenic additive resistance and better general combining ability for the synthetic hexaploid wheats than for GS50a. Published molecular marker studies on a doubled haploid population between the synthetic hexaploid wheat with best general combining ability (CPI133872) and Janz have shown quantitative trait loci for resistance located in all 3 genomes. Synthetic hexaploid wheats offer a convenient way of introgressing new resistances to P. thornei and P. neglectus from both durum and Ae. tauschii into commercial bread wheats.
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Zwart, R. S., J. P. Thompson, and I. D. Godwin. "Identification of quantitative trait loci for resistance to two species of root-lesion nematode (Pratylenchus thornei and P. neglectus) in wheat." Australian Journal of Agricultural Research 56, no. 4 (2005): 345. http://dx.doi.org/10.1071/ar04223.
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Pratylenchus thornei and P. neglectus are two species of root-lesion nematode that cause substantial yield losses in wheat. No commercially available wheat variety has resistance to both species. A doubled-haploid population developed from a cross between the synthetic hexaploid wheat line CPI133872 and the bread wheat Janz was used to locate and tag quantitative trait loci (QTLs) associated with resistance to both P. thornei and P. neglectus. Wheat plants were inoculated with both species of nematode in independent replicated glasshouse trials repeated over 2 years. Known locations of wheat microsatellite markers were used to construct a framework map. After an initial single-marker analysis to detect marker-trait linkages, chromosome regions associated with putative QTLs were targetted with microsatellite markers to increase map density in the chromosome regions of interest. In total, 148 wheat microsatellite markers and 21 amplified fragment length polymorphism markers were mapped. The codominant microsatellite marker Xbarc183 on the distal end of chromosome 6DS was allelic for resistance to both P. thornei and P. neglectus. The QTL were designated QRlnt.lrc-6D.1 and QRlnn.lrc-6D.1, for the 2 traits, respectively. The allele inherited from CPI133872 explained 22.0–24.2% of the phenotypic variation for P. thornei resistance, and the allele inherited from Janz accounted for 11.3–14.0% of the phenotypic variation for P. neglectus resistance. Composite interval mapping identified markers that flank a second major QTL on chromosome 6DL (QRlnt.lrc-6D.2) that explained 8.3–13.4% of the phenotypic variation for P. thornei resistance. An additional major QTL associated with P. neglectus resistance was detected on chromosome 4DS (QRlnn.lrc-4D.1) and explained a further 10.3–15.4% of the phenotypic variation. The identification and tagging of nematode resistance genes with molecular markers will allow appropriate allele combinations to be selected, which will aid the successful breeding of wheat with dual nematode resistance.
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Thompson, J. P., J. G. Sheedy, and N. A. Robinson. "Resistance of Wheat Genotypes to Root-Lesion Nematode (Pratylenchus thornei) Can be Used to Predict Final Nematode Population Densities, Crop Greenness, and Grain Yield in the Field." Phytopathology® 110, no. 2 (February 2020): 505–16. http://dx.doi.org/10.1094/phyto-06-19-0203-r.
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The root-lesion nematode Pratylenchus thornei is a major pathogen of wheat (Triticum aestivum) in many regions globally. Resistance of wheat genotypes to P. thornei can be determined from final nematode population densities in glasshouse experiments but combining results across multiple experiments presents challenges. Here, we use a factor analytic method for multiexperiment analysis of final population densities of P. thornei for 1,096 unique wheat genotypes in 22 glasshouse experiments. The resistance to P. thornei of the genotypes was effectively represented by a two-factor model with rotation of the axes to a principal components solution. Principal axes 1 and 2 (PA1 and PA2) accounted for 79 and 11% of the genetic variance, respectively, over all experiments. Final population densities of P. thornei as empirical best linear unbiased predictors (PA[1+2]-eBLUPs) from the combined glasshouse experiments were highly predictive (P < 0.001) of final nematode population densities in the soil profile, crop canopy greenness (normalized difference vegetation index), and grain yield of wheat genotypes in P. thornei-infested fields in the Australian subtropical grain region. Nine categories of resistance ratings for wheat genotypes from resistant to very susceptible were based on subdivision of the range of PA(1+2)-eBLUPs for use in growers’ sowing guides. Nine genotypes were nominated as references for future resistance experiments. Most (62%) Australian wheat genotypes were in the most susceptible three categories (susceptible, susceptible to very susceptible, and very susceptible). However, resistant germplasm characterized in this study could be used in plant breeding to considerably improve the overall resistance of Australian wheat crops.
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Bahmani, Jebraeil, Farhad Khozeini, Shapour Barooti, Saeed Rezaee, and Reza Ghaderi. "PLANT-PARASITIC NEMATODES ASSOCIATED WITH WALNUT IN THE SANANDEJ REGION OF WEST IRAN." Journal of Plant Protection Research 53, no. 4 (October 1, 2013): 404–8. http://dx.doi.org/10.2478/jppr-2013-0060.
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Abstract A survey of plant-parasitic nematodes associated with walnut was carried out in the Sanandej region, of the province of Kurdistan, in western Iran, during the 2011-2012 time period. After taking samples from fifty-four localities and then doing the routine laboratory work for processing, fixing, and mounting of the nematodes, twenty-one species of plant-parasitic nematodes were finally identified. Among the identified species: Cacopaurus pestis, Mesocriconema xenoplax, Pratylenchus vulnus and Meloidogyne incognita are likely to cause damage. Spiral (Helicotylenchus crassatus, H. digonicus, H. pseudorobustus and H. vulgaris), ring (Mesocriconema antipolitanum and M. xenoplax) and root-lesion nematodes (Pratylenchus neglectus, P. thornei, P. vulnus and P. delattrei) were the most predominant nematodes in the sampled area (frequencies in soil were 87.0, 77.8, and 72.2% and 46.3, 20.4 and 14.8% in root samples, respectively). In the present study, Pratylenchus delattrei, Trophurus lomus, Paratylenchus similis, Geocenamus stegus, Helicotylenchus crassatus, Scutellonema brachyurus and Meloidogyne incognita were reported as new species associated with walnut in Iran.
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Castillo, P., N. Vovlas, and R. M. Jiménez-Díaz. "Pathogenicity and histopathology of Pratylenchus thornei populations on selected chickpea genotypes." Plant Pathology 47, no. 3 (June 1998): 370–76. http://dx.doi.org/10.1046/j.1365-3059.1998.00240.x.
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İMREN, Mustafa. "Bazı Ekmeklik Buğday Çeşitlerinin Kök Yara Nematodları Pratylenchus thornei ve Pratylenchus neglectus’a (Tylenchida: Pratylenchidae) Karşı Dayanıklılıklarının Belirlenmesi." Tarım Bilimleri Dergisi 21, no. 1 (December 24, 2014): 61. http://dx.doi.org/10.15832/tbd.76467.
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Reen, Roslyn A., Michael H. Mumford, and John P. Thompson. "Novel Sources of Resistance to Root-Lesion Nematode (Pratylenchus thornei) in a New Collection of Wild Cicer Species (C. reticulatum and C. echinospermum) to Improve Resistance in Cultivated Chickpea (C. arietinum)." Phytopathology® 109, no. 7 (July 2019): 1270–79. http://dx.doi.org/10.1094/phyto-02-19-0047-r.
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Pratylenchus thornei, a nematode species that feeds and reproduces in chickpea (Cicer arietinum) roots, is widespread throughout the Mediterranean basin and Indian subcontinent. In Australia, it can cause yield losses up to approximately 25% of intolerant chickpea cultivars. Potential for improvement has been hindered by the narrow genetic diversity of cultivated chickpea and a limited world collection of original wild Cicer spp. in the primary gene pool, consisting of 18 C. reticulatum and 10 C. echinospermum accessions. Recently, collections of C. reticulatum and C. echinospermum from Turkey have substantially increased the number of accessions. This study evaluated 133 C. reticulatum and 41 C. echinospermum accessions from the new collection for resistance to P. thornei under controlled conditions in repeated glasshouse pot experiments. The aim of the study was to identify accessions with resistance superior to that currently available in Australian germplasm. Both wild Cicer spp. were found, on average, to be more resistant to P. thornei (P < 0.001) than C. arietinum. Combined analyses across experiments to determine genetic rankings showed that 13 (7%) wild accessions were significantly more resistant than the most resistant C. echinospermum reference ILWC 246, while another 40 (23%) accessions were significantly more resistant than the least susceptible Australian chickpea cultivar PBA Seamer. Mean P. thornei population densities differed significantly between collection sites in Turkey and within each of the genetic population groups. The sites Kayatepe and Baristepe1, and genetic population groups Ret_A and Ret_F associated with sites Oyali and Baristepe1, produced the lowest P. thornei population densities. This is the first report assessing the resistance to P. thornei of this new collection which offers novel sources of P. thornei resistance and untapped genetic diversity valuable for international chickpea breeding programs to exploit.
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Fatemy, S., E. Abootorabi, N. Ebrahimi, and F. Aghabeigi. "First Report of Pratylenchus neglectus and P. thornei Infecting Canola and Weeds in Iran." Plant Disease 90, no. 12 (December 2006): 1555. http://dx.doi.org/10.1094/pd-90-1555b.
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Cultivation of canola (Brassica napus L.) is relatively new in Iran. Because nearly 90% of Iran's edible oil is imported, farmers are subsidized and encouraged to grow this crop. Except for the sugar beet cyst nematode, Heterodera schachtii, to which susceptibility of some canola cultivars has been established (1), information on other nematode pests of canola is lacking. During a survey from April—May 2002 and repeated in 2003, soil and root samples of winter canola and weeds were collected at harvest of canola from research stations and farmers' fields in the south, west, and northwest of Tehran Province. Each sample was a composite of 25 roots and 2 kg of soil per hectare, collected from the rhizosphere of canola with a 2.5-cm-diameter soil corer. Samples were put in plastic bags and kept at 5°C until they were processed, within 2 weeks from sampling. Samples were sieved through a 0.840-cm aperture sieveand mixed thoroughly. Nematodes were extracted from subsamples of 5 g of roots and 250 g of soil with a modification of the sugar centrifugal flotation method (2), counted, and identified. Two species of root lesion nematodes, Pratylenchus neglectus and P. thornei, were found. When they were present in the same field, they occurred in the roots of both Regents × Cobra and Orient cultivars. Averages of 28 and 321 P. thornei per gram were found in the roots of cvs. Regents × Cobra and Orient, respectively. Averages of 30, 1,026, 626, and 450 P. neglectus per gram of roots of cvs. Regents × Cobra, Orient, Ocapi, and GLSIO were detected, respectively, in different fields. Heavily infected plants were stunted and had roots with dark lesions, a symptom typical of the attacks by these nematodes. Generally, greater nematode densities were in the roots than in the soil and both nematode species were more abundant in cooler than in warmer areas of the province. Since these nematodes are also severe pests of wheat, which is also grown in the province, they could pose a potential threat to both crops. Weeds that were present in the sampled fields belonged to the botanical families Scrophulariaceae, Gramineae, Euphorbiaceae, Crucifereae, and Compositeae. Between 22 and 1,500 P. thornei and 17 P. neglectus per gram of roots of Crucifereae and 280 P. thornei per gram of roots of Gramineae were found. To our knowledge, this is the first report of lesion nematodes infecting canola plants in Iran. References: (1) S. Fatemy and E. Abootorabi. Nematol. Mediterr. 30:163, 2002. (2) W. R. Jenkins. Plant Dis. Rep. 48:692, 1964.
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Vanstone, V. A., A. J. Rathjen, A. H. Ware, and R. D. Wheeler. "Relationship between root lesion nematodes (Pratylenchus neglectus and P. thornei) and performance of wheat varieties." Australian Journal of Experimental Agriculture 38, no. 2 (1998): 181. http://dx.doi.org/10.1071/ea97109.
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Summary. The root lesion nematodes Pratylenchus neglectus andP. thornei occur throughout the cereal cropping areas of South Australia. In 1996, field trials on the Eyre Peninsula of South Australia were assessed to determine the relationship between density of nematodes within field plots in early October and harvested grain yield of 9 wheat varieties. The Pratylenchus species present was either P. neglectus (at Streaky Bay, Minnipa and Kalanbi) or P. thornei (at Nunjikompita). Absence of other major yield limiting factors at these sites in 1996 enabled determination of the relationship between nematode population and wheat yield. There was a significant, negative correlation between mean yield and nematode populations for the 9 varieties at 3 of the sites (P<0.01 for Streaky Bay and Nunjikompita; P<0.05 for Minnipa). Root lesion nematodes were responsible for 56–74% of the observed varietal differences in yield at these sites. The tolerant variety Excalibur yielded 19% (Streaky Bay), 23% (Minnipa) or 33% (Nunjikompita) more than the intolerant variety Spear, and Excalibur resulted in 69, 63 or 66% fewer nematodes, respectively, than in plots of Spear. Although nematode populations could not be assessed at the Kalanbi site, varietal yield relations were similar to the other sites, with Excalibur yielding 18% more than Spear. The 9 varieties were ranked for both resistance and tolerance to the 2 nematode species.
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Yavuzaslanoglu, Elif, Ozlem Ates Sonmezoglu, Nimet Genc, Z. Mutlu Akar, Atilla Ocal, M. Sait Karaca, I. Halil Elekcioglu, V. Soner Ozsoy, and Metin Aydogdu. "Occurrence and abundance of nematodes on onion in Turkey and their relationship with soil physicochemical properties." Nematology 21, no. 10 (2019): 1063–79. http://dx.doi.org/10.1163/15685411-00003275.
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Summary The distribution of plant-feeding and free-living nematodes in large scale onion production areas in five geographical regions in Turkey was investigated in 2016 and 2017. Ditylenchus spp. and Tylenchus spp. were widely distributed. The stem and bulb nematode, Ditylenchus dipsaci, was found in 48 locations from 13 provinces. Other plant-feeding nematode genera were Pratylenchus, Paratylenchus and Pratylenchoides. Pratylenchus thornei was the most widely distributed root-lesion nematode species in onion fields in 11 locations from seven provinces. Pratylenchus neglectus was present in three locations and P. vulnus was in four locations. Aphelenchus spp. and Aphelenchoides spp. were the principal fungal-feeding nematodes in onion-growing areas. The most abundant bacterial-feeding nematode genera were Acrobeloides, Cephalobus, Eucephalobus and Rhabditis. Acrobeles and Wilsonema genera were low in occurrence and abundance. Nematodes from Dorylaimida and predator nematodes, Mononchus spp., were also found. The numbers of Ditylenchus from plant samples were significantly correlated positively to silt content, and significantly correlated negatively to organic matter and calcium content.
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Mojtahedi, H. "First Report of Pratylenchus thornei on Dry Land Wheat in Washington State." Plant Disease 72, no. 2 (1988): 175. http://dx.doi.org/10.1094/pd-72-0175c.
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